posted on 2023-04-11, 20:44authored byHaneul Kim, Joonwoo Kim, Ja Hun Kwak
Herein, we show that the weak interaction of CO with
Pt/TiO2 under the CO oxidation condition is the origin
of higher
CO oxidation activity of Pt/rutile than that of Pt/anatase. The results
of CO temperature-programmed desorption (TPD) and in situ diffuse
reflectance infrared Fourier transform spectroscopy (DRIFTS) indicate
that the onset temperatures of CO desorption on freshly prepared Pt/rutile
and Pt/anatase are the same. However, the CO-TPD curves of Pt/rutile
after the reaction test show that the desorption temperature of CO
shifts to a lower temperature, while that for Pt/anatase does not
change. The in situ pulse reaction using DRIFTS reveals that CO on
Pt/rutile reacted with oxygen faster than CO on Pt/anatase. IR spectra
with peak deconvolution of adsorbed CO on Pt/rutile exhibit that CO
adsorbed on the terrace sites of Pt clusters on rutile (2089 cm–1) reacts readily with O2. These results
indicate that the higher low-temperature activity of Pt/rutile is
related to its weaker interaction with CO compared with Pt/anatase
under the reaction conditions. Our findings deepen the fundamental
understanding of metal–support interaction and CO oxidation
on Pt/TiO2 catalysts.